[Taxacom] validation of taxon names

Richard Pyle deepreef at bishopmuseum.org
Sat Feb 18 13:33:53 CST 2012

> Rich, wasn't it you in the past who pointed out the importance of
> circumscription to this endeavor? I think one could realistically say that
> any well-characterized (with respect to types) circumscription there is
only a
> single valid name. Maybe what we need is a better way to code
> circumscriptions.

Yes, I agree -- but the perpetually unanswerable argument is: "which
circumscription best represents the species-level boundaries".  I agree,
with a clear circumscription, there is one "correct" name to use (in theory
-- but different interpretations of the Codes and incomplete nomenclature
can fuzz that up a bit).  But the trouble is that people often disagree on
the best circumscription to use (lumpers v. splitters, etc.).

I agree, that with a better mechanism for encoding circumscriptions, we
could at least have cleaner conversations about this (I think this is part
of what phylogenetic nomenclature approaches are on about, except that they
tend to strictly define circumscriptions in terms of clades, which gets
messy when introgression/hybridization is at play).  Without realizing it
(in most cases), taxonomists tend to use one of several different proxies
for taxon circumscriptions, with different levels of granularities:

- Types/Names-based (each type specimen of a name represents a sign post
within a circumscription, and circumscriptions are defined by which of these
sign posts fall within them).  Basically, this is represented as a synonymy,
and the heterotypic synonyms are proxies for the type specimens, which are
the sign posts.

- Population-based (populations are defined -- often in terms of geographic
distributions -- and these populations are used as more collective sets of
organisms to represent circumscription boundaries).  This approach is less

- Specimen-based (many specimens/individuals are enumerated as members of a
taxon concept circumscription, to provide a richer set of circumscription
boundaries). This is often the approached taken on taxonomic revisions, with
large lists of "Material Examined".  The specimens are often representatives
of entire populations, so this method is similar to the previous, except
with finer granularity.

- Character-based (taxon circumscriptions are defined by sets of
characters).  This is probably the most widely used way of establishing
taxon concept/circumscription boundaries.  I think it's probably the most
practical, but in my mind is less explicit, because at best the characters
are proxies for individual organisms, and I think most people think of taxon
concepts as circumscriptions of organisms, rather than of character states.

There are others on this list who understand this stuff FAR better than I.


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